Terminal structure



Sept. 27, 1938. C, C ABBOTT I 2,131,577

TERMINAL STRUCTURE Filed Oct. 21, 1936 Inventor: Charles C. Abbott,

by/w

At torney.

Patented Sept. 27, 1938 UNITED STATES PATENT OFFICE TERMINAL STRUCTURE New York Application October 21, 1936, Serial No. 106,847

3 Claims.

This invention relates to terminal structures, more particularly to terminal structures for electric heaters, and it has for its object the provision of an improved terminal structure of this 5 character.

While not limited thereto, this invention is particularly applicable to terminal structures for electric heaters of the sheathed type wherein a resistance conductor is mounted in a metallic 110 sheath and supported in spaced relation with reference to the sheath by a compacted mass of heat conducting and electrically insulating material; and more especially to electric space or air heaters of the type described and claimed in my 15 United States Patent No. 1,904,594, dated April 'I'his invention contemplates an improved terminal structure which has a simple, rugged and relatively inexpensive construction.

go For a more complete understanding of this invention, reference should be had to the accompanying drawing in which Fig. 1 is a fragmen. tary plan view of an electric heater provided with terminal structure embodying this invention, 25 parts being broken away so as to illustrate certain details of construction; Fig. 2 is a fragmentary elevation of the electric heater of Fig. 1, parts being broken away and parts shown in section so as to illustrate certain details of conn struction; Fig. 3 is an enlarged view mainly in section illustrating a portion of the terminal structure used in the heater of Figs. 1 and 2; Fig. 4 is a bottom plan view of the terminal structure shown in Fig. 3; Fig. 5 is a bottom plan view of a part of the terminal structure of Fig. 3; Fig. 6 is a fragmentary plan view of an electric heater of modified form embodying the terminal structure of this invention; Fig. 7 is an enlarged bottom plan view of a portion of the terminal struco ture used in the heater of Fig. 6; Fig. 8 is a fragmentary view of still another electric heater using the terminal structure arranged in accordance with this invention; and Fig. 9 is an enlarged fragmentary plan view of the terminal structure o used in the heater of Fig. 8, parts being shown in section to illustrate certain details of construction.

Referring to the drawing, this invention has been shown in one form as applied to an electric 50 space or air heater of the type described in my above-mentioned patent, and comprising a resistance conductor I mounted in a metallic sheath or casing II. As shown, the resistance conductor I0 extends back and forth in a plurality of parallel lengths between a pair of supporting insulators I2 and I3 secured in the end portions of the sheath. The resistance conductor III is supported in spaced relation with reference to the sheath by a compacted mass of powdered heat refractory electrically insulating material Il, such as magnesium oxide. The supporting insulators, I2 and I3, as shown, are provided with series of grooves I5 and I6 respectively receiving the resistance conductor and holding it in its proper position in the sheath 10 I I. The insulator I3 also supports suitable Wirelike terminals II and I8 which are secured to the extreme ends of the resistance conductor I0.

The terminals I`I and I8 lie Within recesses I9 and provided for them in the insulator I3, as 15 shown in Fig. 1. The terminal members are connected with the end turns of the resistancev conductor, as clearly shown in Figs. l, 2 and 3. For the purpose of making the connections, the end turns ofkthe conductor are reduced in diam- 20 eter as compared with the turns of the main portion of the conductor and are swaged or compressed on the ends of the terminals, as shown. At the opposite end of each terminal member there is provided a looped portion 23 defining an 25 eyelet 24. This looped portion is defined by forming the end portion of the terminal into a ring with the extreme end of the wire brought in against the body of the terminal and extended for a short distance against the body and parallel with it, as clearly shown in Fig. 4.

The eyelet 2l of each terminal is secured to a terminal connection member 25. The member 25 is in the form of a nut having a base portion 26, and a pair of anges 21 extending from the 35 base portion on opposite sides thereof and in substantially parallel relation with each other, as clearly shown in Fig. 5. 'I'hese iianges as shown have the form of an arc of a circle the radius of which is the center of a nut. Between o these flanges and extending through the nut is a centrally arranged aperture 28 having its axis coincident with the axis of the anges. The eyelet 24 is mounted on the base of the nut between the two ilanges withthe axis of the eyelet substantially coincident with the axis of the centrally arranged aperture 28. 'I'he anges are peaned or bent over the eyelet, as clearly shown in Figs. 3 and 4, so as to rigidly secure the eyelet, and hence, the terminal to the connection member 25. The flanges may be peaned or bent over in any suitable manner as by means of suitable dies. The aperture 28 through the nut and the inner walls of the eyelet 23 are then threaded. Preferably, the nut will have been threaded before the eyelet is assembled with it, and then after the eyelet has been assembled in the manner previously described, the assembly will be retapped so as to provide a finished threaded aperture of the proper dimensions formed both in the walls of the nut and the inner walls of the eyelet 2l.

The nut it of each terminal is received in a recess lll provided for it in the insulator i3, as clearly shown in Fig. 2. The upper surface of the nut, as viewed in this figure and also in Fig. 3, is presented to the under surface oi the upper wall of the sheath, and between the sheath and the nut is an insulating sheath formed oi any suitable material, such as mica. This insulating sheet, as shovm, is rectangular in shape, and is received in a similarly shaped recess lila. pro vided for it in the insulator i3.

Extending into the sheath through apertures provided for them in the sheath are terminal pins 3l which, as shown, are threaded and 'which are received in the threaded apertures provided in 'the nuts 25 and the eyelets 2li-l. Surrounding each pin 3l in the aperture in the sheath is an insulating disc li/lounted upon each pin 3l intermediate its ends is a shoulder and inter posed between this shoulder and the outer surn face oi the sheath is a sheet or insulating; material ill. Preferably, a metallic washer will be inserted between the shoulder and the sheet dil. it will be understood that the pin received in threaded relation with the terminal will be in very good electrical and mechanical contact with the terminal.

The upper end of the terminal pin il is also threaded, and threaded on this portion is a nut 3b. rlhe nut is arranged to secure between it and the shoulder 33 a suitable electncal connec-1 tion member 3l, shown in Fig. 3 as a circular wire conductor wrapped around the terminal pin. In order to insure a good electrical Contact beu tween the electrical conductor 3l and the terminal pin, the adjoining faces of the shoulder 33 and the nut 3G are dished or tapered inwardly ol these members and away from each other, as clearly shown in Fig. 3, to define wedge-like surfaces, which when the nut 36 is turned inwardly tight against the wire 3l cooperate to force the wire inwardly against the terminal pin. If desired, and it is often preferable to do so, thin metallic washers 38 may be interposed between the shoulder and nut respectively and the wire 31. The washers initially are flat, but take the shape of the shoulder and nut when the nut is turned in.

It will be understood, of course, that any sultable connection member may be secured to the terminal pin 3l by the nut and shoulder. For example, a suitable bus bar may be used to connect a plurality of heaters together. When this is done, it is desirable to stagger the position of the two terminal pins 3|, as clearly shown in Fig, l. In other Words, the two terminal pins are positioned at different lengths from the ends of the sheath so that the bus bars may be strung along at right angles to the axis of the sheaths when used to connect a plurality of heaters together.

Where it is desired to connect two resistance conductors in parallel, the terminal has a somewhat different form. As shown in Figs. 6 and 7, two resistance conductors 39 and 40 of substantially hair-pin shape are nested one within the other and are mounted in a metallic sheath 4|. In this case, let it be assumed that it is desired to connect the two resistance conductors in parallel.

In such an arrangement, the terminal members 42 are formed of a wire member similar to the members ll and I8 of Fig. l, but the eyelet 43 instead of being formed substantially at one end of the wire is formed in the center of the wire, and the two ends of the wire are brought out opposite each other in spaced relation, as clearly shown in Fig, 6. @therwise the terminal structure is substantially the same as that previously described.

8 and 9, there is illustrated an electric heater of the same form shown in Figs. 6 and 7, except in this case it is desired that a relatively portion oi the terminal end oi the sheath be unheated. lin other words, relatively long terminals are used. .ds shown in Fig.' 8, there,

two resistance conductors 474i and 45 arranged as are the conductors 35 and lill of 6 and connected to terminal members t6, which in general have the same iorm as the terminal members of G and l. 'in order to support the inner ends of the legs or the terminals 46 in proper relation with reference to the sheath, suitable insulating supporting members 4l are provided. rhe members dl are formed oi a suitable electrically insulating material, such as porcelain. These members are provided with centrally arranged apertures i8 extending therethrough and in these apertures there are received metallic bushings it which in tuin are mounted directly on the legs oiv the terminal member. As shown, the metallic bushings are secured against endwise movement on the legs oi the terminal by flattening, sir/aging or pressing the extreme right end portions of the sleeves onto the legs, as shown in lig. 9. This swaging or compressing forms flattened sections 50 in the sleeves and 5l in the terminal legs which interlock with each other and thereby prevent movement of the sleeves on the legs. 'I'he opposite ends oi the bushings or sleeves 49 are provided with collars lit. The insulators 41 are prevented from substantial longitudinal movement relative to the terminals by means of these collars and the flattened sections 50 at the opposite ends of the sleeves.

It will be understood that the supports 41 will be mounted on the terminal legs before the resistance conductors are attached to the terminais. This may be accomplished by threading the insulators on their sleeves 49 and then threading the sleeves 49 onto the terminal legs, properly positioning them on the legs, and then providing the flattened sections 50, 5l in the sleeves and legs.

While I have shown particular embodiments of my invention, it will be understood, cf course, that I do not Wish to be limited thereto since many modifications may be made, and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. Terminal structure comprising a wire-like terminal member having a looped section defining an eyelet, a. connection member having a base fitted to one side of said eyelet and having parts directed up anduov'er the sides of. the eyelet to clamp it to (the base, the eyelet being threaded and the base having a threaded aperture registering with the threaded eyelet, and a terminal pin threaded through said base and eyelet.

2. Terminal structure comprising a terminal having a looped portion defining an eyelet, a nut connection' member having a base fitted to one side of said eyelet and portions extending from the base and folded over the eyelet to clamp the terminal to the nut, said nut and terminal having a tapped aperture extending through the eyelet and nut, the threads of the aperture being formed in the Walls of the eyelet as well as in the nut, and a terminal pin threaded in said aperture.

3. A terminal structure comprising a nut connection member having a base and spaced parl0 allel flanges extending from the base, a terminal member having an eyelet fitted on said base substantially centrally thereof, and a portion extending from the base through the space between said flanges, the flanges being folded over to tightly grip said eyelet and interlock it with said nut, said nut and eyelet having a tapped apertureZ the threads of which extend into the Walls of said eyelet, and a terminal pin threaded into said aperture.

CHARLES C. ABBOTT. 

